Process for making blankets for printing machines



May s, 1928. 1,668,763

H. DICKSON PROCESS FOR I AKING BLANKBTS FOR PRINTING MACHINES Filed'June 19. 1926 manta M 8.1928.

UNITED" STATES PA-TE ILLINOIS, ASSIGNOR TO IDEAL ROLLER NT OFFICE. f

ILLINOIS, A CORPORATION 01 ILLINOIS.

PROCESS FOR IMA KING- B LANKETS FOR PRINTING MACHINES.

Application filedlune 19,

ing member having a face layer of a soft resilient material.

Heretofore, blankets for the purpose of offsetting in offsetlithography, for backing the paper to be printed in newspaper presses,and for similar uses in various types of printing machinery, have beenmade of rubber reenforced with a backing of woven fabric. The use ofrubber in any printing ma chinery has a great manydi'sadvantages, one ofwhich resides in the fact that oils used in the printing ink cause adeterioration of the rubber. Also, the oil used for lubricating thebearings of cylinders, rol ers, and

other rotatable or movablemembers, freuently works its way onto therubber blanket and likewise causes a deterioration in the blanket.Moreover, the wide range of temperatures encountered in a printing roomaffects .the rubber blanket and causes it to become unduly hardened orsoftened and frequently causes a swelling or shrinking of the blanket,whereby, for example, should the blanket be used for transferringsubject matter on paper a distortion of such matter would result becauseof interference with the proper registering of the subject matter uponthe paper. 1 g

It has been found, as is well known in the art, that rollers used onprinting presses, typewritino machines, and other similar de-- vices,may be made of vulcanized oil, or, an

ordinary roller composition, which latter consists mainly of glue,glycerine and water, and that neither of these materials is appreciablyaffected by oils or temperature conditions. However. it is difiicult tocast a layer of these resilient materials on a flexible backing memberso that it is of a uniform thickness and also in such manner that itproperly adheres to the backing member.

Further, in the casting of such substances. it is practically impossibleto eliminate air or gas cells which are usually present in the material,or if not present, are formed by the casting or mixing process.

As has been pointed out, theuse of a 1926. Serial No. 117,025.

rubber blanket is highly impracticable for the reasons mentioned, and itis therefore one of theobjects of this invention to proyide a processfor making a blanket comprismg a tough flexible backing member having aface layer of a soft resilient material which is not appreciablyaffected by printing inks,

lubricating oils or temperature conditions.

It is a further object of this invention to provide a process for evenlydistributing the soft resilient material over the surface of the backingmember and holding said soft resillent material'in this evenlydistributed man ner until it becomes solid.

A still further object of, this invention is to provide a process whichwill eliminate air or gas cells which may be present in the material orwhich may have formed during the casting or mixing process.

Further objects of this invention will be apparent from the descriptionand drawings forming a part of this specification to which reference maynow be had for a more co1nplete understanding of the characteristicfeatures of this invention, in which drawlugs:

Figure 1 is an axial section of a centrifugal machine prior to the ofapplying the soft resilient material to the backing member;

Fig. 2 is a sectional viewthrough the mold taken on the line 2-2 of Fig.1;

ig. 3 is a sectional view similar to that of Fig. 2 showing theapplication of the soft resilient material to the backing member; and iv Fig. 4 is a sectional View similar to that of Fig. 3 showing theblanket reversed and in use as an offsetting blanket.

eferring more particularly to the drawings, a centrifugal'castingmachine is a mold in shown comprising a bed 11 and head and tail stocks12 and 13 respectively. The tail stock is adjustable longitudinally ofthe bed and is locked to the bed by a hand screw 14.

A cylindrical rotative shell-mold 15, having preferably a thin layer ofwax 15, on the inner surface thereof is supported at its ends by conical17, the mold being provided with friction rings 18 and 19 that beardirectly against the inner faces of said conical centering members. Thecentering member 16 is fixed operation centering members 16,

to a rotative drive shaft 20 which is mounted in suitable bearings 21 fthe head stock. Power is transmitted to said shaft to rotate the mold byany suitable means as for example a pulley 22.

The opposite conical centering and supporting member 17 .is supportedthrough a suitable anti-friction bearing 27 on the tail stock 13 so asto rotate freely with respect to said tail stock. The member 17 is provided with an apical opening through which a feed tube 28 extends, saidtube being in communication with the outlet end of a fun= aid 29 that issupported on the tail stock,

and through which funnel the materials are poured into the mold. I I Inthe-process of )roducmg a blanket-of the class heretofore escribed, atough flexible backing member 30 is positioned within the shell mold 15and held snugly against the inner coaxial surface thereof by means of anadjustable clamping member 31 disposed at each end. The clamping members31 may be formed of two semi-circular disc members held in the desiredrelation with each other by means of a pair of metal strips 32 on eachside thereof tending therethrough and engaging slots 34 in saiddiscs.

After the mold 15 containing the backing material 30 has been assembledin the centrifugal machine 10 between the conical centering andsupporting members 16 and 17, the

machine is set in motion anda quantity of the wax is not the softresilient material in aliquid state, which has been accurately measuredto pro duce a layer 35 of desired thickness, s poured through the funnel29 into the rotating mold, and centrifugal force is developed by therotation of the mold which causes the material to form the backingmember and roduce a layer 35 of uniform thick-.

ness. .ithin a few minutes after being introduced into the mold.- andwhile being held ina layer of uniform thickness against the ,backingmember,'-the soft resilient material becomes solid. This centrifugalforce also functions to draw to the inside of the material, andeliminate therefrom any air or gas cells which maybe present ther in -rAfter the material has firmly "set, the machine is stop as shown in ig.3 of the drawings. case the mold is linedwith'a thin layer ofjwax 15",the mold is subjected to heat to melt the wax and the blanket is easilremoved by releasingthe clamping mem rs. Due to the elasticity of.themateria'l of the blanket,

process 'althoughitcis desirable since .it serves 'to 'removethe blanketmore readily from-the mold. f

Inasmuch as the backing member is flexible and the soft resilientmaterial formed on and fastehed by bolts 33 ex 'and the mold is remarred,

an essential element of this thee-curvature of the blanket is reversedand placed on a revolving cylinder on a mandrel. As it is preferable tohave a margin -36 along the edges of the backing member 30, which marginis not covered with the soft resilient material 35, this margin may beproduced by any preferred method for removing the resilient materialatthis time.

- As shown in Fig. 4 of the drawings, the

blanket now consisting of a flexible backing member 30 having a layer ofsoft resilient material 35 thereon, is fastenedto a cylinder 37 of anoffset press by means of bolts 38 projectingthrough the margin 36 ontothe backin member 30 and into the cylinder, said bl lmket being reversedfrom its position in the mold and having the soft resilient material 35outermost.

Hereinbefore it has been'stated that the i use of a rubber blanketishighly impracticable, but that the use of an ordinary rollercomposition consisting mainly of glue, glycerine and water or, that theuse of vulc oil, would eliminate the undesirable qualities found arubber blanket. In the preparation of these two last named substancesfor use in the mold, practically the same conditions exist inasmuch asthey are both primarily in a liquid state and are thereafter solidified.In the use of an ordinary roller composition, the material is pouredintothe mold .in a melt- .d condition and allowed to cool and therebybecome solid while the mold is rotating. In

oil and sulphur chloride in proper proportions is poured in a liquidstate into the mold the vulcanizing of oil, a mixture of vegetable vwhich mixture, by means of. a chemical reaction, becomes solid within afew minutes after being introduced into the mold and while the mold isbeing rotated. Sinee'the vulcanizin oilorthe aforementioned roll- ,ercomposltion lacks the tenacity, and to it is re erable to uses backingmember 6 meta -This metsl'backing Indy-b0 6f zinc,

hness which the rubber contains brass, 0 any other sheet metal havingflexibility the degree of required. It is preferable tgremployathicknos-of a the me pnnlximstdy 10/1000 of uri'nchin kmg'memhelj, whilethe thick- 55/1000 of an inch which is the cm thickness for blcnkehofofiaet prunes,

,"Itistobe'undecstnodthstthisinvenhnn the. backing member is elastic,the blanket is not to be to a proces'sfor .ness of the vulcaniledoil myapproximate ing a blanket of the dimensions hereinspecis fied inasmuchas various blankets used in connection with printing machines and thelike may have-blankets of different thickness and, as has been stated,the material is accurately measured to produce a layer of any desiredthickness. All dimensions are given for illustrative purposes.

Although it is considered preferable to employ a flexible metal backingmember,it may be desirable to use-woven fabric in some instances. Insuch case, the fabric may be treated in any convenientmanner in order toobtain the necessary qualities and ad-' herence, or it might bedesirable to use several layers of fabric. In any event, the process offorming the blanket by means of a cen- 1 trifugal method of producingthe soft resilient material on a tough flexible backing member andreversing the blanket upon re moval from the roll so as to meet itsvarious uses, wouldnot vary.

While this invention has been described with relation to a particularmethod, it is to be understood that the same is not to be limited exceptin accordance with, the appended claims and the prior art.

1. The process of making a blanket for printing presses and the likewhich comprises applying by centrifugal action a .liq-

uid material to a flexible backing member held against the curvedsurfaceof'a mold said centrifugal action holding said liquid material tosaid backing member during solidification, then withdrawing the blanketfrom said mold and finally reversing the curvature of said blanket.

- form,

. scribed my name. 2. The process of making a blanket for printingpresses and the like which com prises applying by centrifugal force alayer ing the blanket from said mold and finally reversing the curvatureof said blanket. 3. The processof making a blanket for printing pressesand the like which comprises applying by centrifu al action a li uidmaterial to a flexible acking material held against the curved surfaceof a mold and simultaneously eliminating air and gas cells therefromwhile inv a liquid or-semi-liquid then withdrawing the blanket. fromsaid mold and finally reversing the curvature of said blanket.

, 4. The process of making a blanket for printing presses and the llkewhich comprlses applying by centrifugal action a layer of resilientmaterial to a flexible backing member held against the curved surface ofa mold having a lining materialof a lowerfusingl point than-that oftheother material, then eating said linin material to witha draw theblanket from t 1e mold, and finally reversing the curvature of saidblanket.

5. The process of making a. blanket for I printing presses and thelikewhich cbmprises applying by centrifu al action a layer of re silientmaterial to a exible' backin member held against the curved surface 0 amold,

and withdrawing the blanket from said mold and finally reversing thecurvature of said blanket to tool or rind the same on a mandrel to a'desired t ickness.

In witness whereof, I have hereunto sub- HARRY DICKSON.

